1. Field of the Invention
The present invention relates to an artificial surface suitable for making horse tracks.
2. Description of the Related Art
The surface classically used for races and horse shows is grass, which has the disadvantage of being sensitive to freezing and giving rise to a fast wear and tear in the event of heavy use.
For that reason, grass is reserved for tracks that are used only at the summer months or grounds that have a sufficiently large area to enable it to regenerate itself.
When these conditions were not met, we had the idea to generally replace grass with artificial surfaces most often based on fine siliceous sand, if necessary combined with materials such as wood fibers, ashes from thermal power plants or crushed synthetic materials such as polyvinyl chloride.
The surfaces thereby manufactured did not prove to be satisfactory, considering that they degrade as they age and especially that they lack cohesion and do not hold.
When we researched making such artificial surfaces, we initially primarily endeavored to try to obtain layers that were sufficiently load-bearing layers.
Yet, it is known that bearing capacity is an exponential function of the angle of friction in the ground.
Consequently, to increase the bearing capacity, we sought to introduce additional sources of friction into the ground.
The first idea that came to mind for the specialists consisted of trying to adapt—for making artificial surfaces intended for horse tracks—broken-up angular aggregates such as are usually used in road engineering.
It is indeed easy to conceive that such aggregates can, due to their angular character, wedge themselves geometrically against each other under the action of the circulation of vehicles, thereby causing an increase in the bearing capacity by mechanical effect.
However, it proved that such aggregates cannot be appropriate for an equestrian use considering that they impede the hoof of the horses.
Considering that situation, we thought of using siliceous sands, whose bearing capacity is intrinsically insufficient, and stabilizing them by dispersing full synthetic fibers in them, particularly polypropylene fibers.
Such fibers are likely to increase the cohesion and bearing capacity due to the mechanical friction against the grains of sand thereby generated.
However, incorporating fibers into sand can cause difficulty, with the result that the surfaces thereby manufactured are relatively expensive, thereby limiting the use of this technique.
In addition and primarily, incorporating full synthetic fibers into siliceous sand does not yield artificial surfaces suitable for making horse tracks that have satisfactory characteristics from the standpoint of resiliency and flexibility.
To remedy that disadvantage, it has already been proposed to mix additives such as cork or foam into the mixture of sand and fibers, but it was not thereby possible to obtain results that were satisfactory in all respects insofar as the presence of such additives modifies the behavior of the fibers.
Moreover, such flexibility additives are expensive and therefore appreciably increase the cost of the artificial surfaces thereby designed.